org.apache.flink.table.planner.utils.AggregatePhaseStrategy Maven / Gradle / Ivy

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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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 * See the License for the specific language governing permissions and
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 */

package org.apache.flink.table.planner.utils;

import org.apache.flink.table.api.config.OptimizerConfigOptions;

/**
 * Aggregate phase strategy which could be specified in {@link
 * OptimizerConfigOptions#TABLE_OPTIMIZER_AGG_PHASE_STRATEGY}.
 */
public enum AggregatePhaseStrategy {

    /**
     * No special enforcer for aggregate stage. Whether to choose two stage aggregate or one stage
     * aggregate depends on cost.
     */
    AUTO,

    /** Enforce to use one stage aggregate which only has CompleteGlobalAggregate. */
    ONE_PHASE,

    /**
     * Enforce to use two stage aggregate which has localAggregate and globalAggregate. NOTE: If
     * aggregate call does not support split into two phase, still use one stage aggregate.
     */
    TWO_PHASE
}